The anger in the protests, on a hot day in Philadelphia, reflected a widening rift inside the Democratic Party

Supporters of Bernie Sanders who were angry over the recent email leak protested outside of the Democratic National Convention Monday. NBC10's Keith Jones has the details. (Published Monday, July 25, 2016)

Police briefly detained more than 50 people after they tried to storm the barricades outside the Democratic convention Monday evening in a show of anger over Bernie Sanders' treatment by party leaders, even as he urged his supporters to fall in line behind Hillary Clinton.

Several hundred Sanders supporters and other demonstrators converged in the sweltering heat on Broad Street and made their way four miles to the convention site as the gathering was being gaveled to order, chanting "Nominate Sanders or lose in November!" and "Hey, hey, ho, ho, the DNC has got to go!" They carried signs reading, "Never Hillary," ''Just Go to Jail Hillary" and "You Lost Me at Hillary."

As tensions mounted outside the Wells Fargo Center, police moved metal fences into place and closed the nearest subway station to arriving trains. Fifty-five people were issued citations for disorderly conduct when protesters tried to climb over police barricades at the edge of the security zone surrounding the convention, police said.

The anger reflected the widening rift inside the Democratic Party and the convention hall itself between Sanders' supporters and Clinton's. Debbie Wasserman Schultz resigned as Democratic Party chairwoman Sunday over leaked emails suggesting the supposedly neutral Democratic National Committee played favorites during the primaries by siding with Clinton and bad-mouthing Sanders.

Speaking to delegates Monday morning, Sanders implored them to vote for Clinton, generating a chorus of boos.

"Brothers and sisters, this is the real world that we live in," Sanders said. Donald Trump "is a bully and a demagogue."

The protests took shape amid a punishing heat wave, with oppressive humidity and temperatures in the mid-90s, along with the possibility of severe thunderstorms in the evening. The Fire Department handed out bottled water, and a few protesters were treated for heat-related problems.

The citations capped a day of demonstrations around the city on the opening day of the convention.

About 100 Sanders supporters made their way into Philadelphia by marching across the Ben Franklin Bridge from Camden, New Jersey. Among them was Jim Glidden, a salesman from Batavia, New York. He carried a big sign saying the DNC stands for "Dishonest Nefarious Corrupt."

"Only one guy is telling the truth out there," he said, referring to Sanders. "And the DNC shut him up with lies and cheating."

The demonstrators espoused a variety of causes, including economic justice, socialism and marijuana legalization. With Sanders out of the race, some of them were backing Green Party candidate Jill Stein.

Tensions rose when about 50 marchers sat down on Broad Street and refused to move unless the Mississippi state flag with the Confederate emblem was taken down from a lamppost. The flags of all 50 states fly from light poles on the street.

In contrast, the Republican convention last week in Cleveland was held in a bustling part of the city. A heavy police presence and fewer than expected protesters helped authorities maintain order. Only about two dozen arrests were made.

This story has been corrected to show that the Green Party candidate is named Jill Stein, not Streen.